From: Michal Hocko Subject: Re: [PATCH] mm, oom: report compaction/migration stats for higher order requests Date: Mon, 22 Aug 2016 09:02:50 +0200 Message-ID: <20160822070250.GA13596@dhcp22.suse.cz> References: <201608120901.41463.a.miskiewicz@gmail.com> <201608182049.42261.a.miskiewicz@gmail.com> <809abac0-961d-9cc1-ce6b-3227ffc791c7@suse.cz> <201608212319.51001.a.miskiewicz@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: Vlastimil Babka , linux-ext4@vger.kernel.org, linux-mm@kvack.org, Jan Kara , Joonsoo Kim To: arekm@maven.pl Return-path: Content-Disposition: inline In-Reply-To: <201608212319.51001.a.miskiewicz@gmail.com> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org On Sun 21-08-16 23:19:50, Arkadiusz Miskiewicz wrote: > On Friday 19 of August 2016, Vlastimil Babka wrote: > > On 08/18/2016 08:49 PM, Arkadiusz Miskiewicz wrote: > > > On Wednesday 17 of August 2016, Michal Hocko wrote: > > >> On Wed 17-08-16 10:34:54, Arkadiusz Miśkiewicz wrote: > > >> [...] > > >> > > >>> With "[PATCH] mm, oom: report compaction/migration stats for higher > > >>> order requests" patch: > > >>> https://ixion.pld-linux.org/~arekm/p2/ext4/log-20160817.txt > > >>> > > >>> Didn't count much - all counters are 0 > > >>> compaction_stall:0 compaction_fail:0 compact_migrate_scanned:0 > > >>> compact_free_scanned:0 compact_isolated:0 pgmigrate_success:0 > > >>> pgmigrate_fail:0 > > >> > > >> Dohh, COMPACTION counters are events and those are different than other > > >> counters we have. They only have per-cpu representation and so we would > > >> have to do > > >> + for_each_online_cpu(cpu) { > > >> + struct vm_event_state *this = &per_cpu(vm_event_states, > > >> cpu); + ret += this->event[item]; > > >> + } > > >> > > >> which is really nasty because, strictly speaking, we would have to do > > >> {get,put}_online_cpus around that loop and that uses locking and we do > > >> not want to possibly block in this path just because something is in the > > >> middle of the hotplug. So let's scratch that patch for now and sorry I > > >> haven't realized that earlier. > > >> > > >>> two processes were killed by OOM (rm and cp), the rest of rm/cp didn't > > >>> finish > > >>> > > >>> and I'm interrupting it to try that next patch: > > >>>> Could you try to test with > > >>>> patch from > > >>>> http://lkml.kernel.org/r/20160816031222.GC16913@js1304-P5Q-DELUXE > > >>>> please? Ideally on top of linux-next. You can add both the compaction > > >>>> counters patch in the oom report and high order atomic reserves patch > > >>>> on top. > > >>> > > >>> Uhm, was going to use it on top of 4.7.[01] first. > > >> > > >> OK > > > > > > So with > > > http://lkml.kernel.org/r/20160816031222.GC16913@js1304-P5Q-DELUXE OOM no > > > longer happens (all 10x rm/cp processes finished). > > > > Is it on top of 4.7 then? > > Yes, it was on top of 4.7.0. > > > That's a bit different from the other reporter > > who needed both linux-next and this patch to avoid OOM. > > In any case the proper solution should restrict this disabled heuristic > > to highest compaction priority, which needs the patches from linux-next > > anyway. > > > > So can you please also try linux-next with the patch from > > http://marc.info/?l=linux-mm&m=147158805719821 ? > > https://ixion.pld-linux.org/~arekm/p2/ext4/log-20160819.txt > https://ixion.pld-linux.org/~arekm/p2/ext4/log-trace_pipe-20160819.txt.gz > > rm/cp -al x10 succeeded without any OOM > > so the question is - which solution is "the one" for stable/4.7.x ? I will send an email later today with other people reporting pre-mature OOMs later today and will make sure you are on the CC list as well. Thanks for the testing! -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org